The present invention is directed to a fault current limiting resistor and more particularly to a resistor which can dissipate high levels of fault current energy.
The use of resistors of wire in a fault current limiter to dissipate high levels of fault current energy results in a resistor element that is of considerable weight and length. Since high levels of energy are being dissipated, high operating temperatures are characteristic of this type of resistor element. Such high operating temperature has the following important design considerations: spacing between windings, thermal expansion, sag, accelerated oxidation, accelerated corrosion, high temperature tensile strength, high temperature strength of joints and welds, and heat dissipation. In addition, from an electrical standpoint dielectric clearances and high electro-magnetic forces must be taken into account in any support structure design for this type of resistor.
Since the resistance value as well as the energy absorption requirements will vary in the power system, it can be expected that the resistor element dimensions will also change. In the past it has been difficult to accommodate such changes.